\t
.\" Copyright 2002 walter harms (walter.harms@informatik.uni-oldenburg.de)
.\"
.\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
.\" Distributed under GPL
.\" %%%LICENSE_END
.\"
.\" Corrected, aeb, 2002-05-30
.\"
.TH A64L 3 2021-03-22 "" "Linux Programmer's Manual"
.SH NAME
a64l, l64a \- convert between long and base-64
.SH SYNOPSIS
.nf
.B #include <stdlib.h>
.PP
.BI "long a64l(const char *" str64 );
.BI "char *l64a(long " value );
.fi
.PP
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.PP
.BR a64l (),
.BR l64a ():
.nf
    _XOPEN_SOURCE >= 500
.\"    || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
        || /* Glibc since 2.19: */ _DEFAULT_SOURCE
        || /* Glibc <= 2.19: */ _SVID_SOURCE
.fi
.SH DESCRIPTION
These functions provide a conversion between 32-bit long integers
and little-endian base-64 ASCII strings (of length zero to six).
If the string used as argument for
.BR a64l ()
has length greater than six, only the first six bytes are used.
If the type
.I long
has more than 32 bits, then
.BR l64a ()
uses only the low order 32 bits of
.IR value ,
and
.BR a64l ()
sign-extends its 32-bit result.
.PP
The 64 digits in the base-64 system are:
.PP
.RS
.nf
\&\(aq.\(aq	represents a 0
\&\(aq/\(aq	represents a 1
0-9	represent  2-11
A-Z	represent 12-37
a-z	represent 38-63
.fi
.RE
.PP
So 123 = 59*64\(ha0 + 1*64\(ha1 = "v/".
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.ad l
.nh
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.BR l64a ()
T}	Thread safety	MT-Unsafe race:l64a
T{
.BR a64l ()
T}	Thread safety	MT-Safe
.TE
.hy
.ad
.sp 1
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
.SH NOTES
The value returned by
.BR l64a ()
may be a pointer to a static buffer, possibly overwritten
by later calls.
.PP
The behavior of
.BR l64a ()
is undefined when
.I value
is negative.
If
.I value
is zero, it returns an empty string.
.PP
These functions are broken in glibc before 2.2.5
(puts most significant digit first).
.PP
This is not the encoding used by
.BR uuencode (1).
.SH SEE ALSO
.BR uuencode (1),
.\" .BR itoa (3),
.BR strtoul (3)
.SH COLOPHON
This page is part of release 5.13 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%https://www.kernel.org/doc/man\-pages/.
